#include <KFBasedPixelFitter.h>

Inheritance diagram for KFBasedPixelFitter:

Classes
class	MyBeamSpotGeomDet
class	MyBeamSpotHit
Public Member Functions
	KFBasedPixelFitter (const edm::ParameterSet &cfg)
virtual reco::Track *	run (const edm::Event &ev, const edm::EventSetup &es, const std::vector< const TrackingRecHit * > &hits, const TrackingRegion &region) const
virtual	~KFBasedPixelFitter ()
Public Attributes
tuple	KFBasedPixelFitter
Private Attributes
edm::InputTag	theBeamSpot
std::string	thePropagatorLabel
std::string	thePropagatorOppositeLabel
std::string	theTTRHBuilderName
bool	theUseBeamSpot

Detailed Description

Definition at line 20 of file KFBasedPixelFitter.h.

Constructor & Destructor Documentation

KFBasedPixelFitter::KFBasedPixelFitter ( const edm::ParameterSet & cfg )

virtual KFBasedPixelFitter::~KFBasedPixelFitter ( ) [inline, virtual]

Definition at line 23 of file KFBasedPixelFitter.h.

{}

Member Function Documentation

reco::Track * KFBasedPixelFitter::run	(	const edm::Event &	ev,
		const edm::EventSetup &	es,
		const std::vector< const TrackingRecHit * > &	hits,
		const TrackingRegion &	region
	)		const `[virtual]`

Reimplemented from PixelFitter.

Definition at line 95 of file KFBasedPixelFitter.cc.

References SiPixelRawToDigiRegional_cfi::beamSpot, BoundPlane::build(), funct::C, CircleFromThreePoints::center(), TrajectoryStateOnSurface::charge(), DeDxDiscriminatorTools::charge(), funct::cos(), CircleFromThreePoints::curvature(), TrajectoryStateOnSurface::curvilinearError(), GlobalErrorBase< T, ErrorWeightType >::cxx(), GlobalErrorBase< T, ErrorWeightType >::czz(), TransverseImpactPointExtrapolator::extrapolate(), TrackingRecHit::geographicalId(), edm::EventSetup::get(), edm::Event::getByLabel(), TrajectoryStateOnSurface::globalMomentum(), TrajectoryStateOnSurface::globalPosition(), PixelRecoUtilities::inversePt(), TrajectoryStateOnSurface::isValid(), max(), TrackingRegion::origin(), TrackingRegion::originRBound(), TrackingRegion::originZBound(), PV3DBase< T, PVType, FrameType >::perp(), pos, GloballyPositioned< T >::position(), createTree::pp, LargeD0_PixelPairStep_cff::propagator, PtMinSelector_cfg::ptMin, TrackingRegion::ptMin(), TrajectoryStateOnSurface::rescaleError(), GloballyPositioned< T >::rotation(), funct::sin(), funct::sqr(), TrajectoryStateOnSurface::surface(), funct::tan(), thePropagatorLabel, thePropagatorOppositeLabel, theta(), PV3DBase< T, PVType, FrameType >::theta(), theTTRHBuilderName, theUseBeamSpot, patCandidatesForDimuonsSequences_cff::tracker, KFUpdator::update(), PV3DBase< T, PVType, FrameType >::x(), x, PV3DBase< T, PVType, FrameType >::y(), detailsBasic3DVector::y, and PV3DBase< T, PVType, FrameType >::z().

{
  int nhits = hits.size();
  if (nhits <2) return 0;

  edm::ESHandle<TrackerGeometry> tracker;
  es.get<TrackerDigiGeometryRecord>().get(tracker);

  edm::ESHandle<MagneticField> field;
  es.get<IdealMagneticFieldRecord>().get(field);

  edm::ESHandle<TransientTrackingRecHitBuilder> ttrhb;
  es.get<TransientRecHitRecord>().get( theTTRHBuilderName, ttrhb);

  float ptMin = region.ptMin();

  const GlobalPoint vertexPos = region.origin();
  GlobalError vertexErr( sqr(region.originRBound()), 0, sqr(region.originRBound()), 0, 0, sqr(region.originZBound()));

  std::vector<GlobalPoint> points(nhits);
  points[0] = tracker->idToDet(hits[0]->geographicalId())->toGlobal(hits[0]->localPosition());
  points[1] = tracker->idToDet(hits[1]->geographicalId())->toGlobal(hits[1]->localPosition());
  points[2] = tracker->idToDet(hits[2]->geographicalId())->toGlobal(hits[2]->localPosition());

  //
  //initial Kinematics
  //
  GlobalVector initMom;
  int charge;
  float theta;
  CircleFromThreePoints circle(points[0], points[1], points[2]);
  if (circle.curvature() > 1.e-4) {
    float invPt = PixelRecoUtilities::inversePt( circle.curvature(), es);
    float valPt = 1.f/invPt;
    float chargeTmp =    (points[1].x()-points[0].x())*(points[2].y()-points[1].y())
                       - (points[1].y()-points[0].y())*(points[2].x()-points[1].x()); 
    int charge =  (chargeTmp>0) ? -1 : 1;
    float valPhi = (charge>0) ? std::atan2(circle.center().x(),-circle.center().y()) :  std::atan2(-circle.center().x(),circle.center().y());
    theta = GlobalVector(points[1]-points[0]).theta();
    initMom = GlobalVector(valPt*cos(valPhi), valPt*sin(valPhi), valPt/tan(theta)); 
  } 
  else {
    initMom = GlobalVector(points[1]-points[0]);
    initMom *= 10000./initMom.perp();
    charge = 1;
    theta = initMom.theta();
  }
  GlobalTrajectoryParameters initialKine(vertexPos, initMom, TrackCharge(charge), &*field);

  //
  // initial error
  //
  AlgebraicSymMatrix55 C = ROOT::Math::SMatrixIdentity();
  float sin2th = sqr(sin(theta));
  float minC00 = 1.0;
  C[0][0] = std::max(sin2th/sqr(ptMin), minC00);
  float zErr = vertexErr.czz();
  float transverseErr = vertexErr.cxx(); // assume equal cxx cyy
  C[3][3] = transverseErr;
  C[4][4] = zErr*sin2th + transverseErr*(1-sin2th);
  CurvilinearTrajectoryError initialError(C);

  FreeTrajectoryState fts(initialKine, initialError);

  // get propagator
  edm::ESHandle<Propagator>  propagator;
  es.get<TrackingComponentsRecord>().get(thePropagatorLabel, propagator);

  // get updator
  KFUpdator  updator;

  // Now update initial state track using information from hits.
  TrajectoryStateOnSurface outerState;
  DetId outerDetId = 0;
  const TrackingRecHit* hit = 0;
  for ( unsigned int iHit = 0; iHit < hits.size(); iHit++) {
    hit = hits[iHit];
    if (iHit==0) outerState = propagator->propagate(fts,tracker->idToDet(hit->geographicalId())->surface());
    outerDetId = hit->geographicalId();
    TrajectoryStateOnSurface state = propagator->propagate(outerState, tracker->idToDet(outerDetId)->surface());
    if (!state.isValid()) return 0;
//    TransientTrackingRecHit::RecHitPointer recHit = (ttrhb->build(hit))->clone(state);
    TransientTrackingRecHit::RecHitPointer recHit =  ttrhb->build(hit);
    outerState =  updator.update(state, *recHit);
    if (!outerState.isValid()) return 0;
  }
  


  // get propagator
  edm::ESHandle<Propagator>  opropagator;
  es.get<TrackingComponentsRecord>().get(thePropagatorOppositeLabel, opropagator);
  TrajectoryStateOnSurface innerState = outerState;
  DetId innerDetId = 0;
  innerState.rescaleError(100000.);
  for ( int iHit = 2; iHit >= 0; --iHit) {
    hit = hits[iHit];
    innerDetId = hit->geographicalId();
    TrajectoryStateOnSurface state = opropagator->propagate(innerState, tracker->idToDet(innerDetId)->surface());
    if (!state.isValid()) return 0;
//  TransientTrackingRecHit::RecHitPointer recHit = (ttrhb->build(hit))->clone(state);
    TransientTrackingRecHit::RecHitPointer recHit = ttrhb->build(hit);
    innerState =  updator.update(state, *recHit);
    if (!innerState.isValid()) return 0;
  }


  // extrapolate to vertex
  TrajectoryStateOnSurface  impactPointState =  TransverseImpactPointExtrapolator(&*field).extrapolate( innerState, vertexPos);
  if (!impactPointState.isValid()) return 0;

  //
  // optionally update impact point state with Bs constraint
  // using this potion makes sense if vertexPos (from TrackingRegion is centerewd at BeamSpot).
  //
  if (theUseBeamSpot) {
    edm::Handle<reco::BeamSpot> beamSpot;
    ev.getByLabel( "offlineBeamSpot", beamSpot);
    MyBeamSpotGeomDet bsgd(BoundPlane::build(impactPointState.surface().position(), impactPointState.surface().rotation(),OpenBounds()));
    MyBeamSpotHit     bsrh(*beamSpot, &bsgd);
    impactPointState = updator.update(impactPointState, bsrh); //update
    impactPointState = TransverseImpactPointExtrapolator(&*field).extrapolate( impactPointState, vertexPos); //reextrapolate
    if (!impactPointState.isValid()) return 0;
  }

  int ndof = 2*hits.size()-5;
  GlobalPoint vv = impactPointState.globalPosition();
  math::XYZPoint  pos( vv.x(), vv.y(), vv.z() );
  GlobalVector pp = impactPointState.globalMomentum();
  math::XYZVector mom( pp.x(), pp.y(), pp.z() );

  float chi2 = 0.;
  reco::Track * track = new reco::Track( chi2, ndof, pos, mom,
        impactPointState.charge(), impactPointState.curvilinearError());

/*
    vv = outerState.globalPosition(); 
    pp = outerState.globalMomentum();
    math::XYZPoint  outerPosition( vv.x(), vv.y(), vv.z()); 
    math::XYZVector outerMomentum( pp.x(), pp.y(), pp.z());
    vv = innerState.globalPosition(); 
    pp = innerState.globalMomentum();
    math::XYZPoint  innerPosition( vv.x(), vv.y(), vv.z()); 
    math::XYZVector innerMomentum( pp.x(), pp.y(), pp.z());

    reco::TrackExtra extra( outerPosition, outerMomentum, true,
                      innerPosition, innerMomentum, true,
                      outerState.curvilinearError(), outerDetId,
                      innerState.curvilinearError(), innerDetId,  
                      anyDirection);
*/

//  std::cout <<"TRACK CREATED" << std::endl;
  return track;
}

Member Data Documentation

KFBasedPixelFitter::KFBasedPixelFitter

Initial value:

cms.PSet(
    ComponentName = cms.string('KFBasedPixelFitter'),
    useBeamSpotConstraint = cms.bool(True),
       beamSpotConstraint = cms.InputTag('offlineBeamSpot'),
    propagator = cms.string('PropagatorWithMaterial'),
    propagatorOpposite = cms.string('PropagatorWithMaterialOpposite'),
    TTRHBuilder = cms.string('PixelTTRHBuilderWithoutAngle')
)

Definition at line 3 of file KFBasedPixelFitter.py.

edm::InputTag KFBasedPixelFitter::theBeamSpot [private]

Definition at line 62 of file KFBasedPixelFitter.h.

std::string KFBasedPixelFitter::thePropagatorLabel [private]

Definition at line 59 of file KFBasedPixelFitter.h.

Referenced by run().

std::string KFBasedPixelFitter::thePropagatorOppositeLabel [private]

Definition at line 60 of file KFBasedPixelFitter.h.

Referenced by run().

std::string KFBasedPixelFitter::theTTRHBuilderName [private]

Definition at line 63 of file KFBasedPixelFitter.h.

Referenced by run().